Presentation on theme: "Mesozoic Era: Age of Reptiles"— Presentation transcript:
1Mesozoic Era: Age of Reptiles Chapter 13, Section 3
2Mesozoic HistoryThe Mesozoic era spanned about 183 million years, and it is divided into three periods: the Triassic, Jurassic, and CretaceousThe Mesozoic era began with much of the world’s land above sea level (very few marine fossils are found in North America from the Triassic Period)In the Cretaceous, shallow seas invaded much of western North America creating great swamps (leaving large coal deposits)A major event of the Mesozoic era was the breakup of PangaeaThis process lasted for 200 million years, forming the Atlantic OceanIt also caused the North American plate to override the Pacific plate, causing massive deformation, forming the Sierra Nevada and Rocky Mountains
4Concept Check Explain how the Atlantic Ocean was formed. A rift developed during the breakup of a Pangaea that widened and eventually became the Atlantic Ocean.
5Mesozoic LifeWhen the Mesozoic began, its life forms were the survivors of the great Paleozoic extinctionGymnosperm – seed-bearing plant that bears its seeds on the surface of conesUnlike the first plants to invade land, gymnosperms were not restricted to living near the water’s edge, and they could take advantage of nutrients and space available in drier areasThe gymnosperms quickly became the dominant plants of the MesozoicGymnosperm trees included the cycads, the conifers, and the ginkgoesAmong the animals, reptiles readily adapted to the drier Mesozoic environment, being the first true land animals
7Reptiles DominateWith the perfection of the shelled egg, reptiles quickly became the dominant land animalsThey continued this dominance for 160 million yearsDinosaur – land-dwelling reptile of the Mesozoic eraThe reptiles made an amazing adaptation, one previously made by insects, they began to fly (the pterosaurs)Another group of reptiles led to the more successful flyers—the birdsSome reptiles also returned to the sea, but retained their reptile teeth and breathed with their lungsAt the end of the Mesozoic, many reptile groups became extinctOnly a few types of reptiles survived to recent times (the turtles, snakes, crocodiles, and lizards)Most scientists believe that the extinction of the large reptiles was caused by a large meteorite that collided with Earth